1. Field of the Invention
The present invention relates to operations in a wellbore associated with the production of hydrocarbons. More specifically, the invention relates to systems for developing and producing dual-lateral wells.
2. Description of the Related Art
Often in the recovery of hydrocarbons from subterranean formations, wellbores are drilled with multiple highly deviated or horizontal portions that extend through separate hydrocarbon-bearing production zones. Each of the separate production zones can have distinct characteristics such as pressure, porosity and water content, which, in some instances, can contribute to undesirable production patterns. Many onshore and offshore fields with multiple reservoirs utilize high level technology advancement multi-lateral (TAML) systems to provide the ability to produce two separate reservoirs with different pressure regimes and separate lateral access. However such high level TAML systems are costly due to very expensive equipment, and the significant number of rig operating days required for their use. TAML systems also historically have an inherent risk of completion problems and failures.
As a separate matter, any workover involving entry into a branched lateral portion of a well in an open hole environment can be lengthy, costly, and introduce risk due to uncertainties in entering the branched lateral portion. Entering a particular lateral is often done by trial and error using a bent-sub as a guide and rotating an associated tool string in order to orient the guide. A measurement while drilling (MWD) device on a tool is sometimes used to help orient the guide, and a retrievable bridge plug or a drillable plug is sometimes installed in the motherbore in connection with these techniques to act as a temporary barrier. So if a lateral wellbore is tagged by any tool at the bottom of the string, the tool string can be pulled back up and reworked into the desired lateral wellbore. This is not always practical because typical completion equipment has a limited torque capability and often requires a ball operated pressure release device that precludes use of a MWD tool. Also, rotating completion equipment accidently across the window exit from, the motherbore can damage the equipment.
Another approach sometimes employed for entering a lateral bore involves running and setting a retrievable whipstock in the exact location and orientation of a previous whipstock location, so that the whipstock can easily guide any work string into the lateral wellbore. However, this approach is not often attempted because setting a whipstock at an exact location and orientation along an existing wellbore remains a challenge and retrieval of the whipstock may not be always assured.